金基金屬玻璃薄膜於表面電漿感測器之應用

本論文探討金基金屬玻璃薄膜用於表面電漿感測器之可行性，包括基於局域表面電漿共振及基於傳播表面電漿共振之感測器。首先，我們利用磁控共鍍法製備了四種不同成分之非晶AuCuSi金屬玻璃薄膜。利用奈米壓印試驗機確定了金屬玻璃薄膜之玻璃轉化溫度，此溫度為材料從彈性/塑性形變方式向粘性流動轉變的臨界點。證實了使用Berkovich和圓頭探針之奈米壓痕蠕變測試可適用於測量AuCuSi金屬玻璃薄膜之粘性。流動活化能同樣可以通過奈米壓痕實驗計算獲得，並且利用Berkovich探針和圓頭探針可得到很好的一致性。第二，我們驗證了AuCuSi金屬玻璃薄膜於表面傳遞電漿共振感測器應用之可行性。利用金屬玻璃薄膜，因分子附著引起的周圍環境之折射率變化可通過變角度反射光譜感測。相較於傳統純金薄膜，AuCuSi金屬玻璃薄膜同樣具有對待測物良好的感測性，且相較於純金薄膜AuCuSi具有良好的基板附著力第三，金屬玻璃薄膜在過冷液相區之熱塑性可被用來在薄膜表面製作微米以及奈米等級之微結構以用以表面拉曼散射增強基板。經研究發現，AuCuSi金屬玻璃薄膜之介電常數符合用於表面拉曼散射增強基板之要求。基於金屬玻璃在過冷液相區之可流動性，採用奈米壓印技術，金屬玻璃薄膜被製造成帶有週期性陣列之表面增強拉曼散射基板，這種方式可有效降低製造成本及製造難度。我們利用光學模擬尋求最佳的奈米壓印結構，並完成對壓印生成的不同奈米結構之表面拉曼散射增強基板的光學性質測試，包括反射、散射光譜以及基板之感測靈敏度。本研究成功製備了多種基板，壓印結構尺寸從微米到小於100奈米。壓印製得的基板可有效增強四氨基苯硫酚分子及甲基紫10B分子之拉曼訊號，其中對甲基紫10B分子訊號增強可達1.4×105 倍。最後，本文探討了AuCuSi金屬玻璃薄膜做為針尖增強拉曼光譜（TERS）活化層的可行性。由於實驗條件限制，僅通過光學模擬證明金屬玻璃薄膜可用於代替傳統純金鍍層。因AuCuSi薄膜之硬度約為純金薄膜硬度的三倍且與探針基材有更強附著力，預計金屬玻璃鍍層可大幅提升探針之壽命，具備良好的應用前景。

關鍵字

金屬玻璃；薄膜；奈米壓痕；流變學；奈米壓印；局域表面電漿共振；傳播表面電漿共振；表面拉曼散射增強；針尖拉曼增強光譜

並列摘要

The purpose of this thesis is to investigate the feasibility that the Au-based thin film metallic glasses (TFMGs) could be utilized for plasmonic sensor applications, including localized surface plasmon resonance (LSPR) based sensor and propagating surface plasmon resonance (PSPR) based sensor. Firstly, we synthesized four compositions of fully amorphous AuCuSi TFMGs by magnetron co-sputtering. The glass transition temperature, which is also the temperature of the critical transition point from elastic/plastic deformation to time-dependent viscous flow, was determined using nanoindentation. The nanoindentation creep tests performed with hemispherical and Berkovich indenter tips at temperature range of 50 oC–170 oC were proven to be suitable for the viscosity measurements of AuCuSi TFMGs. The activation energy of the flow process was also evaluated from the indentation results and good agreement was obtained between the results evaluated from hemispherical and Berkovich tips. Finally, a nano-scaled imprinted AuCuSi. Secondly, we verified the feasibility that the AuCuSi TFMG could be applied to PSPR based sensor. By using the AuCuSi TFMG, the refractive index change of surrounding environment could be observed by angel resolved reflection spectrum. Compared with traditional used Au thin film in PSPR based sensor, AuCuSi TFMG also exhibit good sensitivity to the analytes and much better adhesion force to the substrates. Thirdly, thermal plastic forming ability of the as-deposited thin films in their super-cooled liquid regions (SCLR) were utilized to fabricate micron- and nano-scaled patterns as surface enhanced Raman scattering (SERS) substrates. Our study showed that AuCuSi TFMGs process the required dielectric properties for SERS applications. To fabricate periodic arrays for SERS, nano-imprint lithography, a method based on the fluidity of TFMGs in the SCLR, was applied to reduce the cost and complexity of traditional manufacture. Our optical simulation results provided the guidelines for processing of optimum imprinted nano-structures on the Au-based TFMGs. Optical properties, including reflection and scattering, were characterized for SERS substrates and the sensitivity of these substrates were estimated subsequently. Various patterns with the features size from sub-100 nm to micrometer and Raman enhancement factor of crystal violet up to 1.4×105 were achieved. Finally, the feasibility that the AuCuSi TFMG could be used as the activation layer for the Tip-enhanced Raman microscope (TERS) was verified. However, subject to experimental resources, only optical simulations were accomplished, which gave strong evidence that traditional pure Au films could be replaced by AuCuSi TFMG. As the hardness of AuCuSi was about three times higher than that of pure Au and better adhesion force to the substrates, we predicted that AuCuSi will extend the life-time of the TERS tips and has excellent potential for applications.

並列關鍵字

Metallic glass ； Thin film ； Nanoindentation ； Rheology ； Nano-imprint lithography ； Localized surface plasmon resonance ； Propagating surface palsmon resonance ； Surface-enhanced Raman Scattering ； Tip-enhanced Raman spectroscopy